JPH0140004Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a length measuring device with a temperature correction function.

<Background of the invention> In order to investigate deformation due to aging or temperature changes in various structures or structures, it is required to measure minute changes in dimensions.

<Purpose of the invention> The purpose of this invention is to provide a length measuring device with a temperature correction function that can meet these requirements.

<Example of the invention> An example of the invention is shown below in Figure 1. 1st
The figure is a front view for explaining the external appearance of the length measuring instrument according to this invention, FIG. 2 is a sectional view taken along the line - shown in FIG. 1, and FIG. 3 is a sectional view taken along the line - shown in FIG. 1. The example shown in the figure shows a state in which dimensional changes due to thermal expansion of the rail are measured. In other words, as shown in Figure 2, there are two pins 2a on rail 1,
2b is installed, measures the dimension between these pins 2a and 2b, and calculates the axial stress accumulated in the rail 1 by correlating it with the temperature of the rail at that time. show. Therefore, hereinafter, the rail 1 will be referred to as the object to be measured.

In the figure, numeral 3 indicates an attachment that can be attached to the object to be measured 1 by a detachable mechanism. That is, the attachment 3 is fixed to the object to be measured 1 by the knob nut 3a. Attachment 3 has a fixing plate 4
is installed. The fixing plate 4 is fastened and fixed to the attachment 3 with a thumb screw 5 so that the plate surface is horizontal. At this time, the thumb screw 5 passes through an elongated hole 6 (see FIG. 2) formed in the fixing plate 4, and the elongated hole 6 allows the fixing plate 4 to move forward and backward with respect to the object to be measured 1. It has a structure that can be adjusted so that it is in contact with the object to be measured 1.

Reference numeral 7 indicates a length measuring instrument main body supported on the fixed plate 4. This length measuring device main body 7 has rollers 8 on the bottom surface as shown in FIG. It is now possible to move to

Next, the internal structure of the length measuring device main body 7 will be explained using FIGS. 4 and 5.

In FIGS. 4 and 5, reference numeral 9 indicates a substrate that supports the length measuring device main body 7. As shown in FIG. Reference numeral 11 indicates a cover that covers the substrate 9. 12 is a fixed length measuring piece. This fixed length measuring piece 12 is fixed to the substrate 9, and its tip protrudes to the outside through a window 11a formed in the cover 11 so that it can come into contact with the object to be measured 1. 13 indicates a movable length measuring piece. This movable length measuring piece 13 is connected to the movable rod 1
4, and can be moved in a direction parallel to the object to be measured 1 by moving the movable rod 14.

The movable rod 14 is connected to a minute displacement sensor 16 via a biasing means 15. The biasing means 15 includes a cylinder 17, a flange 18 attached to the free end of the movable rod 14, and the flange 18 and the cylinder 17.
A spring 19 is inserted between the end of the spring 19 and the end of the spring 19. According to this biasing means 15, the movable rod 14 receives a biasing force in the right direction in the illustrated state. This biasing force is received by the stopper 20, and the stopper 20 pushes the surfaces 12a and 13a of the fixed length measuring piece 12 and the movable length measuring piece 13.
The distance L is set to a predetermined value. The distance L is set to a value slightly larger than the inner distance between the pins 2a and 2b. This setting is performed using the stopper 20 at a standard temperature of 20°C. Sho 2
1 indicates an attachment for fixing a cylindrical cylinder 17 on the substrate 9. That is, this attachment 21 has a rectangular outer shape and has a hole in the center thereof through which the cylinder 17 passes, and the cylinder 17 is fitted into this hole. One surface of the square attachment 21 is brought into contact with the substrate 9, and the square attachment 21 is screwed from the back side of the substrate 9.

As the minute displacement sensor 16, for example, a differential transformer or a displacement sensor such as Magnescale (trade name) can be used. The example in the figure shows the case where Magnescale is used. 16a indicates a detection head portion. The detection head portion 16a has a through hole into which a movable element, that is, a magnetic scale 16b is inserted. The end of the magnetic scale 16b is connected to the end of the movable rod 14 via an attachment 22.

Since the body holding the minute displacement sensor 16 is simply inserted into the end of the cylinder 17, in this example, the body of the minute displacement sensor 16 is pressed by the leaf spring 23, and the minute displacement sensor 16 is inserted into the cylinder 17. It is designed to be held without wobbling.

Reference numeral 24 indicates an operating lever for moving the movable length measuring piece 13 in the direction of arrow X. This operating lever 24
is rotated and biased counterclockwise by a spring 25, and its tip 24a is biased in a direction away from the movable length measuring piece 13. A rotation support shaft 26 of the lever 24 is connected to a deceleration means 27. The speed reduction means 27 can be constructed, for example, by a gear train connected in multiple stages. Rotate the lever 24 clockwise,
When the lever 24 is released from the rotational operation state, the lever 24 is rotated counterclockwise by the biasing force of the spring 25. At this time, the rotational speed of the lever 24 is limited by the deceleration means 27, and the lever 24 operates to return to its original position at a constant low speed.

Reference numeral 28 indicates that when the operating lever 24 is rotated clockwise, the operating lever 24 is at its maximum rotation position.
Shows the locking lever for keeping it locked.
A disk 29 is attached to the rotation support shaft 26 of the operating lever 24, and a circular arc-shaped long groove 31 is formed in the disk 29, and a recess 32 is formed at the end of the long groove 31. The locking lever 28 is moved to the shaft 3 by the biasing force of the spring 33.
It is biased counterclockwise around point 4. Therefore, the operating lever 24 is rotated clockwise, and when the maximum rotation position is reached, the pin 35 attached to the tip of the locking lever 28 engages with the recess 32, and the operating lever 24 is rotated counterclockwise. prevent it from happening and keep it in that state. To release this locked state, the free end of the locking lever 28 can be pressed. In this manner, the locking lever 28 is rotated clockwise about the shaft 34 and the pin 35 is removed from the recess 32, whereby the operating lever 24 is released from the locked state and begins to rotate counterclockwise at a low speed.

At this time, the movable length measuring piece 13 follows the rotation of the operating lever 24 and moves at a low speed in the direction of arrow X'.

35 indicates a temperature sensor attached to the substrate 9. This temperature sensor 35 mainly measures the temperature inside the board 9 and cover 11 and sends it to the outside from the connector 36 as an electrical signal. A detection signal from the minute displacement sensor 16 is also supplied to the connector 36, and can be taken out to the outside.

FIG. 6 shows the electrical configuration of the length measuring device according to this invention. In FIG. 6, 16 indicates a minute displacement sensor. If Magnescale is used as this minute displacement sensor 16 as described above, the movable element 1
A pulse is output when the magnetic head 6b is displaced relative to the magnetic head portion 16a. By counting these pulses, the amount of movement of the movable rod 14 can be determined. Pulses are output as multiphase pulses, and the phases of multiple pulses are reversed depending on the direction of movement. Therefore, the direction of movement can be determined by the phase of this multiphase pulse, and the amount of movement can be detected by counting the number of pulses. 37 indicates an up-down counter, and this up-down counter 37
The multiphase pulses output from the minute displacement sensor 16 are up-counted and down-counted according to their phases. In other words, the movable length measuring piece 13 is
When the movable length measuring piece 13 moves in the direction of the arrow X', the up/down counter 37 counts down, and when the movable length measuring piece 13 moves in the direction of the arrow X', it counts up. The numerical value of the up-down count 37 and a signal to be converted into a distance from the distance constant circuit 39 are supplied to a distance calculation circuit 38, which converts it into a distance value, and this distance value is supplied to a correction circuit 40. Correction circuit 40
Then, the signal corresponding to the temperature output from the temperature sensor 35 is converted into a digital signal by the A/D converter 41, and this digital signal is provided to the correction value calculation circuit 42. A signal corresponding to the distance value L is supplied to the correction value calculation circuit 42 from the distance constant circuit 39. Further, a signal corresponding to the linear expansion coefficient is given from the linear expansion coefficient setting device 43, and a temperature correction signal is calculated. This temperature correction signal is mainly used to correct the amount of expansion and contraction that occurs in the substrate 9 and the movable rod 14 due to temperature changes. The correction value Δl is obtained by Δl=Lα(t ₂ −t ₁ ) (1). Here, L is the value of the maximum distance between the measuring pieces 12-13, α is the coefficient of linear expansion of the substrate 9 and the movable rod 14, _t1 is the standard temperature (for example, 20°C), and _t2 is the measurement temperature.

The correction value Δl obtained from the correction value calculation circuit 42 is given to the correction circuit 40, and in addition to the measured distance value, the measured distance value is subjected to temperature correction. The corrected distance signal is given to the display 44 and its value is displayed.

<Operation of the device> The operation sequence of the length measuring device described above is as follows.

(1) Attach the attachment 3 to the object to be measured 1 with the fixing plate 4 retracted in advance.

(2) After attaching the attachment 3 to the object to be measured 1, move the fixing plate forward to bring the tip 4a into contact with the object to be measured 1. At this time, the operating lever 24 is rotated to the maximum rotation position and kept in a locked state.
In this state, the length measuring pieces 12 and 13 are inserted between the mutually opposing pins 2a and 2b implanted in the object to be measured 1. At this time, the fixed length measuring piece 12 is kept in contact with the inner surface of the pin 2a.

(3) When preparations are complete, press the free end of the locking lever 28 to release the lock of the operating lever 24.

(4) The locking lever 28 is rotated slowly by the action of the deceleration means 27, and the length measuring piece 13 is slowly moved toward the pin 2b. When the length measuring piece 13 comes into contact with the pin 2b, the movement of the movable rod 14 is stopped.

(5) The display value displayed on the display 44 at this time is the distance value between the pins 2a and 2b. Operation lever 2
4 is energized again and the measurement is performed again. Repeat this measurement operation as many times as necessary to confirm the measured value.

In other words, when the operating lever 24 is rotated,
Reference distance L predetermined by stopper 20
The number of pulses corresponding to the amount of movement _X1 is subtracted from the amount of movement X1, and the amount of movement _X1 is measured.

When the operating lever 24 is unlocked at that position, the movable length measuring piece 13 slowly moves toward its original position. At this time, the movable length measuring piece 13 is connected to the pin 2a.
Pulses are added until it engages, and the amount of movement X ₂ is measured. When the movable length measuring piece 13 is engaged with the pin 2a and stopped, L-( _X1 - _X2 ) is displayed on the display, and the distance value between the pins 2a and 2b is displayed.

Repeat this measurement operation as many times as necessary to confirm the measured value.

<Effects of the invention> As explained above, according to this invention, the temperature of the substrate 9 and its surrounding temperature are measured, and the distance value between the length measuring pieces 12 and 13 is corrected according to the measured temperature values. As the temperature changes, the length measuring pieces 12 and 13 expand due to thermal expansion of the substrate 9 and the movable rod 14.
Even if the distance value between them changes, the change can be corrected and the initial value can always be maintained. Therefore, accurate minute deformation can always be measured regardless of temperature fluctuations.

Furthermore, since the length measuring device main body 7 is supported on the fixed plate 4 by the rollers 8 with reduced frictional resistance, when the movable length measuring piece 13 comes into contact with the pin 2b of the object to be measured 1,
This contact force can also be applied to the other fixed length measuring piece 12. Therefore, pressure contact force can be applied equally to the pins 2a and 2b, and accurate and precise measurements can be made in this respect as well.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an example of the external appearance of the length measuring instrument according to this invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a sectional view taken along the - line in Fig. 1, and Fig. 4 is a sectional view taken along the - line in Fig. 1.
The figure is a partially sectional plan view to explain the internal structure of the main part of this invention, and Figure 5 is a side view thereof.
FIG. 6 is a block diagram for explaining the configuration of the electric circuit of the length measuring device according to this invention. 1: object to be measured, 2a, 2b: pin, 3: attachment, 4: fixed plate, 7: length measuring device body, 8: roller, 9: board, 12: fixed length measuring piece, 13: movable length measuring piece, 14: Movable rod, 15: Biasing means, 1
6: minute displacement sensor, 16b: movable element, 20:
Stopper, 24: Operation lever, 27: Deceleration means,
40: Temperature correction circuit.

Claims (1)

[Claims for Utility Model Registration] A. A fixed plate that is fixed to the object to be measured by an attachment/detachment mechanism, and B. A device that can slide on this fixed plate in a direction parallel to the object to be measured with as little frictional resistance as possible. C. A fixed length measuring piece fixed to this substrate and having a free end protruding toward the object to be measured; D. A minute displacement sensor fixed to the substrate; E. connected to a movable element;
A movable rod supported movably in a direction parallel to the object to be measured; F A movable length measuring piece attached to the other end of the movable rod; G A biasing force directed toward the free end of the movable rod. H a stopper that abuts the free end of the movable rod biased by the biasing means and supports the movable length measuring piece at a reference point; a deceleration means for moving the movable rod against the biasing force of the biasing means and returning the movable rod to its original position at a low speed when released from that state; A length measuring device having a temperature correction function, comprising: a temperature sensor that measures temperature; and a correction circuit that corrects the distance value measured by the length measurement sensor based on the temperature measured by the temperature sensor.